A magnetic disk device, for example, a hard disk drive (HDD) comprises a magnetic disk which is rotatably provided and a head gimbal assembly. The head gimbal assembly comprises a suspension having a gimbal portion and a magnetic head supported by the gimbal portion.
The magnetic head includes a slider and a head portion provided on the slider. The head portion includes a read element for read and a recording element for write. The slider includes a facing surface (Air Bearing Surface: ABS) which faces a recording layer of the magnetic disk. The ABS includes one or more positive pressure generating surfaces on an upstream side (inflow side) and a downstream side (outflow side) and at least a pair of negative pressure generating grooves on the downstream side. In addition, the ABS has a groove portion lower than the pressure generating surface between a pressure generating surface on an inflow side and a pressure generating surface on an outflow side, and the groove portion is formed on the same surface up to the side portion of the slider.
During an operation of a disk drive, an air flow is generated between the rotating magnetic disk and the slider, and the ABS of the slider is subjected to a force (positive pressure) which flies the slider from a magnetic disk recording surface according to a principle of air fluid lubrication. By balancing the flying force and a head load, the slider flies with a gap from the magnetic disk recording surface.
Although the disk drive is kept at a higher cleanliness, there is contamination such as a small amount of dust or dirt in the drive. Liquid contamination such as a lubricant is mainly stored in a groove of the ABS and flows to the side portion of the slider. The liquid contamination reaching the side portion flows to the downstream side of the magnetic head and finally falls onto the magnetic disk. As a result, a gap between the magnetic head and the magnetic disk is changed, which may adversely affect the magnetic head or the magnetic disk.